The invention relates to a cable connecting device with which an electrically conductive contact can be produced between two current-carrying lines. Cable connecting devices of this kind are used for an extremely wide array of fields in electrical engineering. For a few years now, cable connecting techniques have been used particularly often in the field of photovoltaics, in situations in which rows of individual solar panels are connected to one another in series and then connected to a main line.
There is an extremely wide variety of possible connections, depending on the embodiment of the solar collector system. So-called T-joints are frequently used, for example, when a series of solar panels is connected to the main line as described above, but cross connections (X connections) are another frequently used connection type.
When electric cable connections are used in the field of photovoltaics, especially the T-joint situated closest to the current infeed point of the solar collector system is subjected to particularly high loads due to the elevated current flow by comparison with the rest of the system. Also, the devices belonging to photovoltaic systems are exposed to extremely difficult environmental conditions. The temperatures can easily fluctuate from for example −5° C. to +40° C., solar radiation is unusually high, and the system and its components such as lines and connections are particularly exposed to humidity and frost.
Conventional connections, in particular the connections between individual solar panels, are frequently “crimped” or connected by means of a plug connector system. “Crimping” is understood to be a joining process in which two components are joined to each other by means of plastic deformation. A crimped connection is only partially detachable and is usually not repairable. Crimping is an alternative to conventional connections such as soldering or welding; crimped connections are usually used to attach the plug connector elements.
Soldered or welded connections or plug connectors are generally used in connection locations that are subjected to particularly high loads, e.g. in connection locations like the above mentioned T-joint situated closest to the current infeed point. In soldering, which like welding, is a thermal process for integrally joining materials, the electrical conductors are connected to each other by melting a solder (soldering).
Crimping, soldering, and welding, however, are not always suitable for use in photovoltaic systems. This is because photovoltaic systems are generally designed for a service life of 30 years, which is frequently the reason for early failure of the above-mentioned electrical connections.
In addition, soldering and welding share the fact that producing a soldered or welded connection requires an array of equipment such as soldering irons, solder, holding devices, and gas canisters, burners, etc. to be brought along. This is cumbersome and sometimes dangerous, particularly on roofs on which solar collector systems are typically installed. Soldered or welded connections also require insulation after the joining process, which is accomplished by means of heat-shrinking sleeves and the application of heat.
Fundamentally speaking, the use of this method is therefore comparatively expensive with regard to the required time and necessary logistics. This is not desirable either in a new installation of a photovoltaic system or when repairing electrical connections that have failed due to environmental influences and/or aging.